CLEARSY is investing to become a major player in the ERTMS/ETCS field. We are supporting our customers with our expertise, products and services.

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A CLEARSY specific unit specialised in ERTMS

CLEARSY has created a specific unit specialised in ERTMS, composed of very experienced persons, who participated in the genesis of the project in the 90s, notably through their involvement in the UIC A200 project which built the first versions of the system, and who closely follow the evolution of the European norms from the origin.

This unit is offering services (consulting, training, test, …) and products/tools (HMI, test benches, formal data validation tools, tools related to braking curves…).

CLEARSY is designing and producing software related tools and products:

CLEARSY is offering services

  • Expertise and technical assistance
  • Translation of needs to clear specifications
  • Preparation/evaluation of tenders
  • Design and development of software for safety critical or simulation applications
  • Validation tests (compliance to requirements)
  • Training

Development of software applications for industry

Specialised in the production of ERTMS/ETCS related solutions

We are specialised in the production of ERTMS/ETCS related solutions, in the field of simulation tools for research, demonstration, testing and training, but also in safety related products for on-board or trackside applications. We perform also consulting and training activities.


Founded in 1998 as a part of the former ERRI (European Railway Research Institute), ERSA has participated to the development of the first ETCS simulator in Europe within the frame of the UIC A200 project.

In the frame of a contract with UNISIG (at the time also called “Eurosig”), ERSA provided a set of tools used for the creation of the first independent test bench for ETCS on-board systems in Europe, in the premises of CEDEX in Madrid. As a participant of different European projects, ERSA had the opportunity to develop a number of software products used for the demonstration and testing of ETCS. ERSA has provided simulation solutions to the three Laboratories recognised as references in Europe (CEDEX, DLR and MULTITEL).

ERSA follows very closely the development of new European standards and is currently helping the European Railway Agency and the ERTMS Users Group in the consolidation of the specifications of Baseline 3, by the provision of various simulation tools, especially a functional implementation of the ETCS on-board system (EVC) and the ETCS Driver Machine Interface.

In 2001, ERSA was acquired by AEA Technology PLC (UK), trading as the rail division. The business was sold in 2006 to Vision Capital LLC with the subsequent creation of DeltaRail Group Ltd. In 2015 the company was sold to its Executive Directors.

Our clients

We deliver our products and services mostly in European countries, but also in Asia. Our customers are Railways Undertakers or Infrastructure Managers, Railways Industries and Research Institutes.

We follow closely the European norms related to ERTMS/ETCS and are helping the European Institutions with the consolidation of the specification. Several tools developed by ERSA are widely used by the sector, such as the Test Sequence Wizard (TSW) and the Test Sequence Debugger (TSD).

In the frame of the UIC ERTMS Training conferences, we are used to demonstrate specific ETCS scenarios with our set of simulation tools.

We have partnerships with Universities involved in ERTMS/ETCS and or simulation activities, like UTC (Compiègne), UTBM (Belfort) or ENSAM (Metz).

We were involved in the following projects:

  • openETCS, in which our company is Work Package Leader for the Demonstrator.
  • ReTrack, in which our company provided a very comprehensive simulator simulating a freight corridor crossing 4 European countries (The Netherlands, Germany, Austria, Hungary).
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